Western blotting is a ubiquitous analytical technique for identifying and quantifying specific proteins in a complex mixture. In the technique, gel electrophoresis is used to separate proteins in a gel based on properties such as tertiary structure, molecular weight, isoelectric point, polypeptide length, or electrical charge. Once separated, the proteins are then transferred from the gel to a membrane—typically made of nitrocellulose, nylon, or polyvinylidene fluoride (PVDF)—that binds proteins non-specifically. A commonly used method for carrying out this transfer is electroblotting, in which an electrical current is used to pull proteins from the gel into the membrane. The membrane is then stained with probes specific for the proteins being targeted, allowing the location and amounts of these proteins to be detected.
Capillary electrophoresis provides an alternative to the gel electrophoresis separation associated with Western blotting and other biotechnology procedures. In capillary electrophoresis, materials such as proteins are separated electrokinetically, as in gel electrophoresis, but with much smaller required volumes. The capillaries used in this technique are typified by diameters smaller than one millimeter and are in some instances incorporated into microfluidic or nanofluidic devices.
There exists in the art a need to improve and advance the technique of Western blotting, as well as other membrane analysis methods such as Northern blotting and Southern blotting. The numerous steps involved with these methods makes them relatively time-consuming, labor-intensive, and prone to errors or variability.